Quantifying sublethal effects of glyphosate and Roundup® to Daphnia magna using a fluorescence based enzyme activity assay and video tracking

Peter Roslev, Lone R. Hansen, Michael Ørsted

Research output: Contribution to conference without publisher/journalConference abstract for conferenceResearchpeer-review

Abstract

Glyphosate (N-(phosphonomethyl)glycine) is the active ingredient in a range of popular broad-spectrum, non-selective herbicide formulations. The toxicity of this herbicide to non-target aquatic organisms such as Daphnia magna is often evaluated using conventional toxicity assays that focus on endpoints such as immobility and mortality. In this study, we investigated sublethal effects of glyphosate and Roundup® to D. magna using video tracking for quantifying behavioral changes, and a novel fluorescence based assay for measuring in vivo hydrolytic enzyme activity (FLEA assay). Roundup® exposure resulted in concentration-dependent inhibition of alkaline phosphatase activity in D. magna. The inhibition of alkaline phosphatase by Roundup® was temperature-dependent with lowest inhibition at 14 °C and greater inhibition at 20 and 26 °C. Exposure of D. magna to sublethal concentrations of glyphosate resulted in behavioral effects quantified as decreases in average swimming velocity and distance moved whereas the inactive time in defined arenas increased. Exposure of D. magna to binary mixtures of glyphosate and copper (Cu) attenuated acute metal toxicity. The results suggest that a combination of assays targeting in vivo enzyme activity and behavioral changes may be applied as a quantitative and sensitive tool for detecting sublethal effects of glyphosate and Roundup® to D. magna. The inhibitory effect of Roundup® on alkaline phosphatase in non-target organisms warrants further investigations.

Key words: Glyphosate, Daphnia magna, sublethal, enzyme activity, video tracking

Original languageEnglish
Publication date2015
Publication statusPublished - 2015
EventSETAC Europe 25th Annual Meeting: Environmental protection in a multi-stressed world: challenges for science, industry and regulators - Barcelona, Spain
Duration: 3 May 20157 May 2015
Conference number: 25

Conference

ConferenceSETAC Europe 25th Annual Meeting
Number25
Country/TerritorySpain
CityBarcelona
Period03/05/201507/05/2015

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